JavaScript: Useful notes

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JavaScript Notes
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To declare an object
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function Rectangle(w, h) {
	this.width = w;
	this.height = h;
};
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Create a new instance of the object
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var myRect = new Rectangle(100,150);

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Methods in js. They are added to the class using the prototype object.
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Rectangle.prototype.area = function() {
	return this.width * this.height;
}

Rectangle.prototype.perimeter = function() {
	return (2*this.width) + (2*this.height);
}
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Objects inheritance
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Step 1
function DepthRectangle(w,h,d) {
	// Call func works like parent::__construct in PHP, call parent's constructor
	Rectangle.call(this,w,h);
	this.depth = d;
}

Step 2
Set the protype object of the subclass to be that of the superclass. Otherwise, we just got a subclass of Object which us not what we want.

DepthRectangle.prototype = new Rectangle();

Step 3
Since the DepthRectangle prototype was created with the Rectangle constructor, we have to re-assign the constructor property to be our DepthRectangle.

DepthRectangle.prototype.constructor = DepthRectangle;

Step 4
Define new methods or overwriting the parent's method.

DepthRectangle.prototype.volume = function() {
	return (this.area() * this.depth);
}

DepthRectangle.prototype.toString = function() {
	return "DepthRectangle with width: " + this.width + " & height: " + this.height + " & depth: " + this.depth;
}

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Reg exp
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| or 
() group things together, can also define subexpressions
Match hello or good bye: /hello|good bye/ 
Match 4 digits or 5 characters: /\d{4}|\w{5}/
Match US postal code with optional 4 digits:
/^\d{5}(-\d{4})?$/

Match a phone number like this 123-4567
/\d{3}-\d{4}/
To be able to extract the individual portions use parentheses

Match a string with single or dubble quotes and anything in between * 0 or more times and match the same quote at the end. \1
/(['"])[^'"]*\1/

Match flags, putting outside the reg exp:
Case insensitive, match hello or HELLO, etc: /hello/i
Global search, match all "hello" strings: /hello/g

RegExp() object
RegExp.test() - Tests this RegExp against a give string
RegExp.exec() - Very powerful expression matching function
RegExp.ignoreCase - Same as i flag
RegExp.global - Same as g flag
RegExp.source - The read-only source string of the pattern
RegExp.lastIndex - The position index of the most recent match